Five Markdown Renderers, One Table: Where They Actually Differ

A Markdown table that looks perfect on GitHub can lose a cell on Zenn, split a row in your Astro blog, or refuse to render on Qiita. Most of the rules are shared. The disagreements are narrow, repeatable, and easy to hit in a docs pipeline.

On 2026-10-02 I sent the same table cases through five renderers:

• GitHub Markdown API
• Gitee Markdown API
• Qiita: qiita_marker 0.23.9.0
• Zenn: zenn-markdown-html 0.5.4 (markdown-it 14.3.2)
• micromark 4, the parser behind remark, MDX and Astro

The full matrix and fixtures are in the guide linked at the end. These are the differences that change output.

1. A backslash before a pipe is read differently

For the cell text x\\|y:

GitHub, Gitee, Qiita, Zenn -> one cell: x|y micromark (remark, MDX) -> two cells: x\ and y 

GitHub and markdown-it treat any pipe after a backslash as escaped. micromark consumes \\ first as an escaped backslash, so the pipe that follows splits the cell.

If you need a literal backslash followed by a pipe, write three backslashes: \\\| shows \| in all five.

2. An unescaped pipe always splits, even inside code

Table rows are split at pipes before cell content is parsed. So `a|b` ends the cell after `a. Write `a\|b`; all five render the code a|b and remove the backslash.

The same applies to a regular expression: (png|jpg) inside a cell must be (png\|jpg).

3. Header and delimiter rows must have the same cell count

| a | b | over |---| is not a table on any of the five. It becomes a paragraph of pipes.

4. A table may interrupt a paragraph

All five start the table right after a text line:

Intro line. | a | b | |---|---| | 1 | 2 | Next paragraph. 

Next paragraph. becomes a fourth row. A blank line after the table is optional for parsing, but it prevents this.

5. A full-width pipe is not a pipe

U+FF5C ｜ is a different character. A table written with ｜ renders as text on all five. This is common when the table was typed with a Japanese or Chinese IME.

6. CJK bold at the start of a cell

**注意：**这里 is not bold on any of the five. CommonMark's delimiter rules require the closing ** to be right-flanking; a following CJK punctuation mark breaks that. Two fixes:

**注意：** 这里 **注意**：这里 

The first keeps the colon inside the bold; the second moves it out. Both render.

7. <br> works, until a sanitizer strips it

GitHub, Gitee, Qiita and Zenn render <br> inside a cell. A site that escapes raw HTML shows the tag as text. Check the target renderer before relying on it.

What to do

• Write \| for a pipe and \\\| for a literal backslash followed by a pipe.
• Add a space after bold when a CJK punctuation mark follows, or move the punctuation outside the bold.
• Never use ｜ as a table separator.
• Keep header and delimiter cell counts equal.
• Test in the renderer that will publish the page. "Works on GitHub" is not a spec.

The measurements, the renderer-by-input matrix, and the JSON fixtures are in the full guide. There is also a Markdown table generator that escapes pipes and can compare the output of these renderers cell by cell.